Jetstar will boost its presence in Adelaide but slash flights from Darwin as the low-cost airline rejigs its schedule in the face of "increased capacity and competition, particularly on international routes from foreign carriers", the airline says.

"Jetstar has been clear in the past that our flying from Darwin is among the most marginal on the network" Jetstar's Hall said. "These changes will ensure we maintain the highest productivity of our aircraft and reflect our strategy to deploy aircraft on routes to meet market demand."